What About Herd Immunity?

This article is Part 4 of a 5-Part series on Vaccines. See the full list of (and links to) the rest in this series below.

Much of the discussion surrounding the vaccine debate centers around the issue of "herd immunity." This is because herd immunity is cited as the pivotal reasoning behind mandatory vaccination campaigns.

In Joe Carter's pro-vaccine Gospel Coalition article, he makes the case that failing to vaccinate puts the "public health" at risk. He points to herd immunity as the reason and describes it in the following manner:

Herd Immmunity vs. Vaccine-Induced Herd Immunity

Original herd immunity theory had nothing to do with vaccines. It was theorized that those who were not immune to contracting a disease were indirectly protected when a critical mass of the population had already contracted the disease and recovered from it. In short, this kind of natural herd immunity is real and effective.

Promoters of mass-vaccination campaigns adopted this theory and applied it to what is regarded as vaccine-induced immunity and theorized that the results would be the same with "wild virus" natural immunity.

The idea is if enough people in a given population are "immunized against a contagious disease" with vaccines, the disease can be eradicated or chances of outbreak plummet. Is it really as simple as that? Some important questions to ask are:

What is the effect of vaccine-induced herd immunity? Does it justify the state mandating vaccination of all children? Are those who decide against vaccination for their children putting public health at risk?

According to analysis conducted by Princeton University researchers, vaccine induced herd immunity "does not exist and is not attainable." They found that "public health policies have not attained herd immunity for any childhood disease despite 60 years of compulsive policies and intensive effort."

Further, they find that the case for mandatory vaccination is based on several "leaps in logic" which rely on presumptions which the study finds to be unsupported:

Not only are mandatory vaccination mandates not justifiable based upon appeals to herd immunity, there is reason to be skeptical regarding the claims that the lack of vaccine induced herd immunity creates a problem or that the unvaccinated present any serious risk to the vaccinated in the first place.

What Happens if We Don't Have Vaccine-Induced Herd Immunity?

Proponents of attempts to create vaccine-induced herd immunity maintain that various thresholds are required to achieve herd immunity for various diseases.

Basically, they're saying that since the effect of most vaccines wears off after 2-15 years, a certain percentage of the population needs to be up to date on their vaccines for herd immunity to work. It's alleged by the CDC that those who receive two doses of measles vaccination are protected for life with 95% efficacy (a number from Merck which is disputed by whistleblowers.)

So what is the community vaccination rate currently in the United States? Well let's be extremely conservative and assume that 100% of children in the US are vaccinated and fully up to date on the CDC schedule (they aren't.) Let's then look at the numbers which the CDC provides for adult vaccination rates across the US.

According to the CDC, the averages are almost all well below 60%. Let's conservatively assume the 60% number, though most vaccination rates for adults are well below that. In the US, those who are aged 18 and over represent 76% of the population. This means that at most even factoring a 100% rate of vaccination for those under 18, the total community vaccination rate is about 69% at the highest. I would imagine the real number is somewhere south of 60%. So if herd immunity requires over 80% vaccination rates, and we are significantly below those rates, the questions becomes: We have outbreaks - but where are all the epidemics for these diseases? And why is it that the outbreaks we do have are frequently in communities with almost 100% vaccinated populations?

Keep in mind, vaccination rates were much lower in the 80's and we had no vaccinations of any kind for a number of diseases currently on the CDC schedule.

Where were all the epidemics in the 1980's? For all these reasons, there is a solid basis for rational, reasonable people to be skeptical regarding the claims of the effectiveness of vaccine-induced herd immunity in the United States .

Do the Unvaccinated Present a Serious Risk to the Vaccinated?

We can all agree that the only people who present an actual risk to infect someone else are those who have the disease themselves. After all, it's impossible to infect someone if you don't carry the disease yourself. So we are not talking about a failure to quarantine the sick, we are talking about a decision not to vaccinate a healthy person who does not have the disease.

The argument goes that since vaccinations don't always work, and since there are some people who can't be vaccinated, everyone else needs to be vaccinated to protect those who can't. But what happens when vaccinating the healthy introduces a health risk of a possible adverse reaction to the vaccine? Now we have a discussion regarding the evaluation of competing risks.

Beyond this, how significant is the risk to the vaccinated?

Dr. Tetyana Obukhanych, a Phd. in immunology and a lab researcher at Harvard & Stanford Universities conducted an analysis of this question and submitted it for review to the Vermont Legislature Senate Health and Welfare Committee who were exploring vaccine legislation. Her well cited findings can be found here.

Obukhanych concluded that, because most of the vaccines on the CDC schedule are either not designed to protect from communicable diseases or they are designed for diseases which are not communicable, the unvaccinated pose no threat to the vaccinated.

For the immuno-vulnerable, she points out that there are other measures available to them:

"Infants as well as other vulnerable or immuno-compromised individuals, are eligible to receive immunoglobulin, a potentially life-saving measure that supplies antibodies directed against the virus to prevent or ameliorate disease upon exposure."

In summary, it is reasonable for people of good faith to be skeptical regarding both the existence of herd immunity, it's efficacy, and the alleged danger it presents to the immuno-vulnerable. When taken together with the apparent risks of vaccination, the decision to withhold vaccination from children cannot ethically bind parents to be forced to vaccinate their children; nor should any person expect them to be banished from the public square.

Further Resources on Vaccine-Induced Herd Immunity

For more information on vaccine-induced herd immunity, see the resources below: